devicefilesystem: Default to accessmode=mapped for qemu

libvirt qemu default's to accessmode=passthrough, which really only
works correctly when qemu is run as root, which isn't common for libvirt
nowadays. So use accessmode=mapped which has a better chance of working

tests/cli-test-xml/compare/virt-install-many-devices.xml

@@ -149,7 +149,7 @@
       <master startport="4"/>
       <address type="pci" domain="0" bus="0" slot="4" function="2"/>
     </controller>
-    <filesystem accessmode="squash">
+    <filesystem type="mount" accessmode="mapped">
       <source dir="/source"/>
       <target dir="/target"/>
     </filesystem>
@@ -157,6 +157,10 @@
       <source name="template_name"/>
       <target dir="/"/>
     </filesystem>
+    <filesystem type="file" accessmode="squash">
+      <source file="/tmp/somefile.img"/>
+      <target dir="/mount/point"/>
+    </filesystem>
     <interface type="user">
       <source portgroup="foo"/>
       <mac address="12:34:56:78:11:22"/>

tests/cli-test-xml/compare/virt-install-singleton-config-2.xml

@@ -81,7 +81,7 @@
     <emulator>/usr/bin/qemu-kvm</emulator>
     <controller type="usb" index="0" model="nec-xhci"/>
     <controller type="virtio-scsi" index="0"/>
-    <filesystem>
+    <filesystem type="mount" accessmode="mapped">
       <source dir="/foo/source"/>
       <target dir="/bar/target"/>
     </filesystem>
@@ -201,7 +201,7 @@
     <emulator>/usr/bin/qemu-kvm</emulator>
     <controller type="usb" index="0" model="nec-xhci"/>
     <controller type="virtio-scsi" index="0"/>
-    <filesystem>
+    <filesystem type="mount" accessmode="mapped">
       <source dir="/foo/source"/>
       <target dir="/bar/target"/>
     </filesystem>

tests/clitest.py

@@ -498,8 +498,9 @@ c.add_compare(""" \
 --hostdev usb_5_20 --hostdev usb_5_21 \
 \
 
---filesystem /source,/target,accessmode=squash \
+--filesystem /source,/target \
 --filesystem template_name,/,type=template,mode=passthrough \
+--filesystem type=file,source=/tmp/somefile.img,target=/mount/point,accessmode=squash \
 \
 --soundhw default \
 --sound ac97 \

virtinst/devicefilesystem.py

@@ -76,7 +76,7 @@ class VirtualFilesystem(VirtualDevice):
         # In case of qemu for default fs type (mount) target is not
         # actually a directory, it is merely a arbitrary string tag
         # that is exported to the guest as a hint for where to mount
-        if (self.conn.is_qemu() and
+        if ((self.conn.is_qemu() or self.conn.is_test()) and
             (self.type is None or
              self.type == self.TYPE_DEFAULT or
              self.type == self.TYPE_MOUNT)):
@@ -111,5 +111,20 @@ class VirtualFilesystem(VirtualDevice):
         return setattr(self, self._type_to_source_prop(), val)
     source = property(_get_source, _set_source)
 
+    def set_defaults(self, guest):
+        ignore = guest
+
+        if self.conn.is_qemu() or self.conn.is_test():
+            # type=mount is the libvirt qemu default. But hardcode it
+            # here since we need it for the accessmode check
+            if self.type is None or self.type == self.TYPE_DEFAULT:
+                self.type = self.TYPE_MOUNT
+
+            # libvirt qemu defaults to accessmode=passthrough, but that
+            # really only works well for qemu running as root, which is
+            # not the common case. so use mode=mapped
+            if self.accessmode is None or self.accessmode == self.MODE_DEFAULT:
+                self.accessmode = self.MODE_MAPPED
+
 
 VirtualFilesystem.register_type()